scholarly journals Climatic, Edaphic and Biotic Controls over Soil δ13C and δ15N in Temperate Grasslands

Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 433
Author(s):  
Xing Zhao ◽  
Xingliang Xu ◽  
Fang Wang ◽  
Isabel Greenberg ◽  
Min Liu ◽  
...  

Soils δ13C and δ15N are now regarded as useful indicators of nitrogen (N) status and dynamics of soil organic carbon (SOC). Numerous studies have explored the effects of various factors on soils δ13C and δ15N in terrestrial ecosystems on different scales, but it remains unclear how co-varying climatic, edaphic and biotic factors independently contribute to the variation in soil δ13C and δ15N in temperate grasslands on a large scale. To answer the above question, a large-scale soil collection was carried out along a vegetation transect across the temperate grasslands of Inner Mongolia. We found that mean annual precipitation (MAP) and mean annual temperature (MAT) do not correlate with soil δ15N along the transect, while soil δ13C linearly decreased with MAP and MAT. Soil δ15N logarithmically increased with concentrations of SOC, total N and total P. By comparison, soil δ13C linearly decreased with SOC, total N and total P. Soil δ15N logarithmically increased with microbial biomass C and microbial biomass N, while soil δ13C linearly decreased with microbial biomass C and microbial biomass N. Plant belowground biomass linearly increased with soil δ15N but decreased with soil δ13C. Soil δ15N decreased with soil δ13C along the transect. Multiple linear regressions showed that biotic and edaphic factors such as microbial biomass C and total N exert more effect on soil δ15N, whereas climatic and edaphic factors such as MAT and total P have more impact on soil δ13C. These findings show that soil C and N cycles in temperate grasslands are, to some extent, decoupled and dominantly controlled by different factors. Further investigations should focus on those ecological processes leading to decoupling of C and N cycles in temperate grassland soils.

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1386
Author(s):  
Michael Stotter ◽  
Florian Wichern ◽  
Ralf Pude ◽  
Martin Hamer

Cultivation of Miscanthus x giganteus L. (Mis) with annual harvest of biomass could provide an additional C source for farmers. To test the potential of Mis-C for immobilizing inorganic N from slurry or manure and as a C source for soil organic matter build-up in comparison to wheat (Triticum aestivum L.) straw (WS), a greenhouse experiment was performed. Pot experiments with ryegrass (Lolium perenne L.) were set up to investigate the N dynamics of two organic fertilisers based on Mis at Campus Klein-Altendorf, Germany. The two fertilisers, a mixture of cattle slurry and Mis as well as cattle manure from Mis-bedding material resulted in a slightly higher N immobilisation. Especially at the 1st and 2nd harvest, they were partly significantly different compared with the WS treatments. The fertilisers based on Mis resulted in a slightly higher microbial biomass C and microbial biomass N and thus can be identified as an additional C source to prevent nitrogen losses and for the build-up of soil organic matter (SOM) in the long-term.


2020 ◽  
Vol 53 (1) ◽  
pp. 19-27
Author(s):  
Adenike Fisayo Komolafe ◽  
Christopher Olu Adejuyigbe ◽  
Adeniyi Adebowale Soretire ◽  
Isaac OreOluwa Olatokunbo Aiyelaagbe

AbstractCompost maturity is a major factor in its use for nutrient supply without adverse effect on crop germination. Composting may be accelerated with inclusion of some microorganisms as activators. This study was conducted to determine the effect of Trichoderma asperellum and length of composting of different plant materials and cattle manure on compost maturity in Ibadan, Nigeria. Composting of two plant materials with cow dung at ratio 3:1 was done in triplicate with or without Trichoderma activation to obtain twelve heaps of four different types of composts; Panicum-based compost with Trichoderma, Tridax-based compost with Trichoderma, Panicum-based compost without Trichoderma and Tridax-based compost without Trichoderma. The process was a 2×2 factorial experiment, laid out a completely randomized design. The Trichoderma activated compost (TAC) at four weeks of composting (4WC) had 56% total N, 21% organic matter, 38% total K, 51% total P and 66.6% microbial biomass N increase over non-activated compost (NAC). Carbon to nitrogen ratio was within the ideal range (10–20) in TAC while it was greater than it in NAC. Microbial biomass and lignin contents had a 56% and 41% increase, respectively, in NAC over TAC. Trichorderma-activated compost has a potential to hasten maturation and makes the compost ready for field on or before four weeks without posing a threat to crop germination.


2011 ◽  
Vol 1 (4) ◽  
pp. 202-207
Author(s):  
N. Ewusi‐Mensah ◽  
V. Logah ◽  
J. O. Fening

This paper reports the short Ã¢â‚¬Â term effects of organic and inorganic fertilizerapplications on the culturable resident bacterial and fungal properties of aFerric Acrisol in the semi Ã¢â‚¬Âdeciduous forest zone of Ghana after three continuouscropping seasons. The treatments were two compost types (i.e. 1:1compost comprising 1 part made up of Chromolaena, Stylosanthes, maizestover mixture and 1 part of cattle manure, 2:1 compost comprising 2 partsof Chromolaena, Stylosanthes, maize stover mixture and 1 part of cattle manure),cowdung, 100% NPK and a control replicated three times in a randomizedcomplete block design. The results showed that total microbial load on alogarithmic scale ranged from 4.6 cfu/g in the control to 5.4 on cowdungtreated plots. Bacterial counts on 2:1 compost applied at 5 t/ha treatedplots recorded 5% more bacteria than the 1:1 compost applied at 5 t/ha.Fungal counts in the control and inorganic treated plots were higher than theorganically amended plots. The highest and lowest microbial biomass C contentswere recorded on cowdung and 1:1 compost at 5 t/ha treated plotsrespectively. Microbial biomass N content ranged from 1.4 Ã¢â‚¬Â 8.2 mg N kg‐1soil with a mean value of 6.2 mg N kg Ã¢â‚¬Â1 soil. Microbial biomass P contentranged from 3.6 Ã¢â‚¬Â 6.3 mg P kg‐1 soil with a mean value of 5 mg P kg‐1 soil.Microbial biomass carbon to organic carbon ratio varied from 18.37 to 85.63.


1995 ◽  
Vol 124 (1) ◽  
pp. 17-25 ◽  
Author(s):  
L. J. Wyland ◽  
L. E. Jackson ◽  
K. F. Schulbach

SUMMARYWinter non-leguminous cover crops are included in crop rotations to decrease nitrate (NO3-N) leaching and increase soil organic matter. This study examined the effect of incorporating a mature cover crop on subsequent N transformations. A field trial containing a winter cover crop of Merced rye and a fallow control was established in December 1991 in Salinas, California. The rye was grown for 16 weeks, so that plants had headed and were senescing, resulting in residue which was difficult to incorporate and slow to decompose. Frequent sampling of the surface soil (0–15 cm) showed that net mineralizable N (anaerobic incubation) rapidly increased, then decreased shortly after tillage in both treatments, but that sustained increases in net mineralizable N and microbial biomass N in the cover-cropped soils did not occur until after irrigation, 20 days after incorporation. Soil NO3-N was significantly reduced compared to winter-fallow soil at that time. A 15N experiment examined the fate of N fertilizer, applied in cylinders at a rate of 12 kg 15N/ha at lettuce planting, and measured in the soil, microbial biomass and lettuce plants after 32 days. In the cover-cropped soil, 59% of the 15N was recovered in the microbial biomass, compared to 21% in the winter-bare soil. The dry weight, total N and 15N content of the lettuce in the cover-cropped cylinders were significantly lower; 28 v. 39% of applied 15N was recovered in the lettuce in the cover-cropped and winter-bare soils, respectively. At harvest, the N content of the lettuce in the cover-cropped soil remained lower, and microbial biomass N was higher than in winter-bare soils. These data indicate that delayed cover crop incorporation resulted in net microbial immobilization which extended into the period of high crop demand and reduced N availability to the crop.


2009 ◽  
Vol 55 (No. 6) ◽  
pp. 223-230 ◽  
Author(s):  
S. Singh Jay ◽  
D.P. Singh ◽  
A.K. Kashyap

This study investigated microbial biomass-N (MB-N) and N-mineralization in soils of four different vegetation systems including forest (sal), mixed forest, savanna and cropland ecosystems in the Vindhyan region, India. A change was noted in the above region due to physiographic differences and anthropogenic disturbances. Annually the soil moisture (SM) content across the different study sites ranged from 7.5 to 24.3% being maximum in forest sites compared to savanna and cropland sites. The NH<sub>4</sub><sup>+</sup>-N, NO <sup>-</sup><sub>3</sub> -N and MB-N concentrations varied from 4.3 to 10.2 &mu;g/g, 1.1 to 5.8 &mu;g/g and 21.3 to 90.2 &mu;g/g dry soil, respectively, with minimum values in the wet and maximum values in the dry season. The trend of seasonal variation in net N-mineralization was similar to that of moisture content but counter to the concentrations of inorganic-N and MB-N. The net N-mineralization rates at different investigated sites ranged from 4.5 to 37.6 &mu;g/g month. Cultivation reduced the N-mineralization and MB-N by 58.5% and 63.5%, respectively. Experiments showed that the percentage contribution of MB-N to total-N was 8.01 to 19.15%. MB-N was positively correlated with the inorganic-N (<i>n</i> = 180,<i>r</i>.80,<i>P</I> < 0.001) but negatively with soil moisture (<i>n</i> = 180, <i>r</i> = 0.79, <i>P</I> < 0.001) and net N-mineralization rates (<i>n</i> = 180, <i>r</i> = 0.92, <i>P</I> < 0.0001). The higher N-mineralization and MB-N in the soil of forest ecosystem was reported compared to savanna and cropland and the order of soil MB-N levels and net N-mineralization followed the sequence: forest (sal) > mixed forest > savanna > cropland.


1969 ◽  
Vol 100 (2) ◽  
pp. 123-140
Author(s):  
Ian C. Pagán-Roig ◽  
Joaquín A. Chong ◽  
José A. Dumas ◽  
Consuelo Estévez de Jensen

The objective of this work was to measure the effects of repeated short-term organic amendments that we termed soil treatment management cycles (STMC) on physical and biological properties of a San Antón series soil. Each STMC lasted 60 days and consisted of incorporating 5% organic matter from coffee pulp compost; the planting, growth and incorporation of an intercrop of four green manure species; and the application of mycorrhizae and compost tea. The treatments were labeled: CL0, CL1, CL2 and CL3; where CL0 was the control, CL1 received one STMC, CL2 and CL3 received two and three STMC, respectively. The STMC intended to mimic the overall effect of a sustainable agricultural system, not to measure the individual effects of the practices. All treatments (CL1, CL2, CL3) showed an increase in soil organic matter (p≤0.05). When compared to the CL0 control, saturated hydraulic conductivity increased and bulk density decreased in all soils. Soil macroporosity was significantly increased by CL2 and CL3. Soil aggregate stability increased in CL1, CL2 and CL3 plots. Microbial biomass C increased in treatment CL3, and microbial biomass N increased in CL2 and CL3. The production of stable aggregates was correlated to humic acid content and positively influenced all other physical parameters assessed in this study. The STMC had a positive impact on soil properties by increasing the soil organic matter as well as the humic acid fraction. Soil macroporosity, defined as porosity with radius > 38 µm, was significantly increased by treatments CL2 and CL3. All of the organic matter fractions, including total organic matter, humic acid content, microbial biomass C and microbial biomass N were significantly increased by one or more STMC.


Author(s):  
Gong ◽  
Zhang ◽  
Guo

: Soil and soil microbial biomass (SMB) carbon: nitrogen: phosphorus (C:N:P) stoichiometry are important parameters to determine soil balance of nutrients and circulation of materials, but how soil and SMB C:N:P stoichiometry is affected by climate change remains unclear. Field experiments with warming and N addition had been implemented since April 2007. Infrared radiators were used to manipulate temperature, and aqueous ammonium nitrate (10 g m-2 yr-1) was added to simulate nitrogen deposition. We found that molar nutrient ratios in the soil averaged 60:11:1, warming and warming plus N addition reduced soil C:N by 14.1% and 20% (P < 0.01), and reduced soil C:P ratios by 14.5% and 14.8% (P < 0.01). N addition reduced soil C:N significantly by 17.6% (P < 0.001) (Figs. 2B, 2D). N addition and warming plus N addition increased soil N:P significantly by 24.6% and 7.7% (P < 0.01). The SMB C:N, C:P and N:P ratios increased significantly with warming, N addition and warming plus N addition. Warming and N addition increased the correlations between SOC and soil microbial biomass C (SMBC), soil total P and soil microbial biomass P (SMBP), warming increased the correlation between the soil total N and soil microbial biomass N (SMBN). After four years’ treatment, our results demonstrated that the combined effects of warming and N fertilization could change the C, N, P cycling by affecting soil and SMB C:N:P ratios significantly and differently. At the same time, our results suggested SMB might have weak homeostasis in Sonnen Grassland and warming and N addition would ease N-limitation but aggravate P-limitation in northeastern China. Furthermore, these results further the current demonstration of the relationships between the soil and SMB C:N:P stoichiometry in response to global change in temperate grassland ecosystems.


1970 ◽  
Vol 25 (1) ◽  
pp. 21-25
Author(s):  
SM Abdur Rahman ◽  
ARM Solaiman

Microbial biomass carbon (C) and nitrogen (N) and their contribution to soil organic carbon and total N contents were assessed in soils collected from Bilashchara Tea Estate under Bangladesh Tea Research Institute (BTRI), Srimangal of Moulavibazar district, and Sripur Tea Garden under Jaintapur of Sylhet district. Microbial biomass C and N in Bila shchara Tea Estate soils varied from 90.4-144.0 and 20.5-29.0 mg/kg soil, and that of Sripur Tea Garden soils varied from 120.7-362.0 and 26.6-59.5 mg/kg soil, respectively. Within the two tea growing areas biomass C/N ratios ranged from 3.35-6.12. Relationships between biomass C and organic carbon and biomass N and total N were positively correlated. The contribution of biomass C to soil organic C was 1.23%, ranging from 0.9-1.55% and the contribution of biomass N to total N content of the soils ranged from 1.19-2.89%. Keywords: Biomass carbon (C); Biomass nitrogen (N); Organic C; Total N; Tea soilDOI: http://dx.doi.org/10.3329/bjm.v25i1.4850 Bangladesh J Microbiol, Volume 25, Number 1, June 2008, pp 21-25


1992 ◽  
Vol 43 (5) ◽  
pp. 1197
Author(s):  
PR Grace ◽  
IC MacRae ◽  
RJK Myers

Microbiological and chemical assays were performed on clay soils from woodland (Acacia harpophylla-Casuarina cristata), grassland (Panicurn maximum var trichoglume-Chloris gayana) and cropland (Vigna mungo) in the brigalow region of Central Queensland. Over a 15 month period, the microbial biomass C in the top 3.5 cm of native brigalow woodland soil was on average 3630 8g C g-l, 50% more than an associated perennial pasture and over 400% more than an annually cropped soil. Microbial biomass N (575 8g N g-l) in woodland soil was on average 41% and 270% higher than in pasture and cropped soils respectively and highly correlated with seasonal soil moisture content. Viable counts of bacteria were consistently lower (average 69.2%) in the 0-3.5 cm and 3.5-7.5 cm strata of woodland soil compared with pasture and annual crop sites. Soil NO-3- N levels increased two fold in the upper 3.5 cm of the woodland site during low rainfall periods. This increase may be attributed to a more efficient distribution of mineral N mediated by the increased presence of a fungal population in this community. Leaching may also play a significant role in the distribution of plant available N in the brigalow region as suggested by the inverse relationship N = 54.11-0.67 R (P<0.01), where N is soil NO-3-N (8g N g-l) and R is rainfall in the preceding 3 month period (mm month-1).


Author(s):  
George O. Odugbenro ◽  
Zhihua Liu ◽  
Yankun Sun

An incubation study was conducted to determine the influence of biochar and corn straw on CO2-C emission, soil organic C, microbial biomass C and N, total N, and mineral N (NH4+-N and NO3--N) in a clay loam soil. Six treatments viz., CK (Control); S (Soil + 1% straw); B1 (Soil + 0.5% biochar); B2 (Soil + 2% biochar); SB1 (Soil + 1% straw + 0.5% biochar); SB2 (Soil + 1% straw + 2% biochar) were tested with three replications. Results showed that straw addition to soil with or without biochar increased CO2-C emission while sole-biochar addition (2%) reduced it. Straw and biochar also increased the soil microbial biomass C and N but greatest increase in microbial biomass N (111.9 µg g-1) was recorded by biochar-straw combination. SOC and total N significantly increased following biochar and straw additions which suggest that organic amendments can improve soil chemical properties. Additionally, for soil mineral N, biochar reduced NH4+-N and NO3--N concentrations while straw increased NH4+-N concentration but greatly reduced that of NO3--N.


Sign in / Sign up

Export Citation Format

Share Document